- ID:
- ivo://CDS.VizieR/J/PASJ/63/1117
- Title:
- Asteroid catalog using AKARI (AcuA). V1.
- Short Name:
- J/PASJ/63/1117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The AKARI Infrared Astronomical Satellite observed the whole sky in the far infrared (50-180{mu}m) and the mid-infrared (9 and 18{mu}m) between May 2006 and August 2007 (Murakami et al. 2007PASJ...59S.369M). The Asteroid catalog using AKARI (AcuA) version 1.0 is the first asteroid catalog produced based on the AKARI/IRC Mid-Infrared Survey. The catalog provides the size and albedo of 5120 asteroids.
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- ID:
- ivo://CDS.VizieR/J/A+A/657/A80
- Title:
- Asteroides phase curves using SLOAN MOC
- Short Name:
- J/A+A/657/A80
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Large photometric surveys are producing, and will continue doing it, massive amounts of data on small bodies. Usually,these data will be sparsely obtained at arbitrary (and unknown) rotational phases. Therefore, new methods to process such data need to be developed to make the most of those large catalogs. We aim to produce a method to create phase curves of small bodies considering the uncertainties introduced not only by the nominal errors in the magnitudes, but also the effect introduced by rotational variations.We use as a benchmark the data from the SLOAN Moving Objects Catalog with the objective to construct phase curves of all small bodies in there, in the u, g, r, i, and z, filters. We will obtain from the phase curves the absolute magnitudes and set up with them the absolute colors, which are the colors of the asteroids not affected by changes in phase angle. We select objects with >3 observations taken in, at least, one filter and spanned over a minimum of 5 degrees in phase angle. We developed a method that combines Monte Carlo simulations and Bayesian inference to estimate the absolute magnitudes using the HG12 photometric system. We obtained almost 15000 phase curves, about 12000 including all five filters. The absolute magnitudes and absolute colors are compatible with previously published data, supporting our method.Conclusions. The method we developed is fully automatic and well suited to be run on large amounts of data. Moreover, it includes the nominal uncertainties in the magnitudes and the whole distribution of possible rotational states of the objects producing, possibly,less precise values, i.e., larger uncertainties, but more accurate, i.e., closer to the real value. To the best of our knowledge, this work is the first to include the effect of rotational variations in such a way.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A80
- Title:
- Asteroid (31) Euphrosyne R-band images
- Short Name:
- J/A+A/641/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Asteroid (31) Euphrosyne is one of the biggest objects in the asteroid main belt and it is also the largest member of its namesake family. The Euphrosyne family occupies a highly inclined region in the outer main belt and contains a remarkably large number of members, which is interpreted as an outcome of a disruptive cratering event.The goals of this adaptive-optics imaging study are threefold: to characterize the shape of Euphrosyne, to constrain its density, and to search for the large craters that may be associated with the family formation event. We obtained disk-resolved images of Euphrosyne using SPHERE/ZIMPOL at the ESO 8.2m VLT as part of our large program (ID: 199.C-0074, PI: Vernazza). We reconstructed its 3D shape via the ADAM shape modeling algorithm based on the SPHERE images and the available light curves of this asteroid. We analyzed the dynamics of the satellite with the \genoid meta-heuristic algorithm. Finally, we studied the shape of Euphrosyne using hydrostatic equilibrium models. Our SPHERE observations show that Euphrosyne has a nearly spherical shape with the sphericity index of 0.9888 and its surface lacks large impact craters. Euphrosyne's diameter is 268+/-6km, making it one of the top ten largest main belt asteroids. We detected a satellite of Euphrosyne - S/2019 (31) 1 - that is about 4 km across, on a circular orbit. The mass determined from the orbit of the satellite together with the volume computed from the shape model imply a density of 1665+/-242kg/m^-3^, suggesting that Euphrosyne probably contains a large fraction of water ice in its interior. We find that the spherical shape of Euphrosyne is a result of the reaccumulation process following the impact, as in the case of (10)Hygiea. However, our shape analysis reveals that, contrary to Hygiea, the axis ratios of Euphrosyne significantly differ from those suggested by fluid hydrostatic equilibrium following reaccumulation.
- ID:
- ivo://CDS.VizieR/J/A+A/561/A45
- Title:
- Asteroid (341843) 2008 EV5 WISE light curves
- Short Name:
- J/A+A/561/A45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the thermal inertia of 2008 EV5, the baseline target for the Marco Polo-R mission proposal, and infer information about the size of the particles on its surface. Values of thermal inertia were obtained by fitting an asteroid thermophysical model to NASA's Wide-field Infrared Survey Explorer (WISE) infrared data. Grain size was derived from the constrained thermal inertia and a model of heat conductivity that accounts for different values of the packing fraction (a measure of the degree of compaction of the regolith particles).
- ID:
- ivo://CDS.VizieR/J/MNRAS/433/2075
- Title:
- Asteroid families identification
- Short Name:
- J/MNRAS/433/2075
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It has been shown that large families are not limited to what found by hierarchical clustering methods (HCM) in the domain of proper elements (a,e,sin(i)), that seems to be biased to find compact, relatively young clusters, but that there exists an extended population of objects with similar taxonomy and geometric albedo, that can extend to much larger regions in proper elements and frequencies domains: the family "halo". Numerical simulations can be used to provide estimates of the age of the family halo, that can then be compared with ages of the family obtained with other methods. Determining a good estimate of the possible orbital extension of a family halo is therefore quite important, if one is interested in determining its age and, possibly, the original ejection velocity field. Previous works have identified families halos by an analysis in proper elements domains, or by using Sloan Digital Sky Survey-Moving Object Catalog data, fourth release (SDSS-MOC4) multi-band photometry to infer the asteroid taxonomy, or by a combination of the two methods. The limited number of asteroids for which geometric albedo was known until recently discouraged in the past the extensive use of this additional parameter, which is however of great importance in identifying an asteroid taxonomy. The new availability of geometric albedo data from the Wide-field Infrared Survey Explorer (WISE) mission for about 100,000 asteroids significantly increased the sample of objects for which such information, with some errors, is now known. In this work we proposed a new method to identify families halos in a multi-domain space composed by proper elements, SDSS-MOC4 (a, i-z) colors, and WISE geometric albedo for the whole main belt (and the Hungaria and Cybele orbital regions). Assuming that most families were created by the breakup of an undifferentiated parent body, they are expected to be homogeneous in colors and albedo. The new method is quite effective in determining objects belonging to a family halo, with low percentages of likely interlopers, and results that are quite consistent in term of taxonomy and geometric albedo of the halo members.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A121
- Title:
- Asteroid (7) Iris Deconvolved disk-resolved images
- Short Name:
- J/A+A/624/A121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Asteroid (7) Iris is an ideal target for disk-resolved imaging owing to its brightness (V~7-8) and large angular size of 0.33'' during its apparitions. Iris is believed to belong to the category of large unfragmented asteroids that avoided internal differentiation, implying that its current shape and topography may record the first few 100Myr of the solar system's collisional evolution. We recovered information about the shape and surface topography of Iris from disk-resolved VLT/SPHERE/ZIMPOL images acquired in the frame of our ESO large program. We used the All-Data Asteroid Modeling (ADAM) shape reconstruction algorithm to model the 3D shape of Iris, using optical disk-integrated data and disk-resolved images from SPHERE and earlier AO systems as inputs. We analyzed the SPHERE images and our model to infer the asteroid's global shape and the morphology of its main craters. Results. We present the 3D shape, volume-equivalent diameter D_eq_=214+/-5km, and bulk density {rho}=2.7+/-0.3g/cm^3^ of Iris. Its shape appears to be consistent with that of an oblate spheroid with a large equatorial excavation. We identified eight putative surface features 20-40km in diameter detected at several epochs, which we interpret as impact craters, and several additional crater candidates. Craters on Iris have depth-to-diameter ratios that are similar to those of analogous 10km craters on Vesta. The bulk density of Iris is consistent with that of its meteoritic analog based on spectroscopic observations, namely LL ordinary chondrites. Considering the absence of a collisional family related to Iris and the number of large craters on its surface, we suggest that its equatorial depression may be the remnant of an ancient (at least 3Gyr) impact. Iris's shape further opens the possibility that large planetesimals formed as almost perfect oblate spheroids. Finally, we attribute the difference in crater morphology between Iris and Vesta to their different surface gravities, and the absence of a substantial impact-induced regolith on Iris.
- ID:
- ivo://CDS.VizieR/J/AJ/150/75
- Title:
- Asteroid light curves from PTF survey
- Short Name:
- J/AJ/150/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We fit 54296 sparsely sampled asteroid light curves in the Palomar Transient Factory survey to a combined rotation plus phase-function model. Each light curve consists of 20 or more observations acquired in a single opposition. Using 805 asteroids in our sample that have reference periods in the literature, we find that the reliability of our fitted periods is a complicated function of the period, amplitude, apparent magnitude, and other light-curve attributes. Using the 805-asteroid ground-truth sample, we train an automated classifier to estimate (along with manual inspection) the validity of the remaining ~53000 fitted periods. By this method we find that 9033 of our light curves (of ~8300 unique asteroids) have "reliable" periods. Subsequent consideration of asteroids with multiple light-curve fits indicates a 4% contamination in these "reliable" periods. For 3902 light curves with sufficient phase-angle coverage and either a reliable fit period or low amplitude, we examine the distribution of several phase-function parameters, none of which are bimodal though all correlate with the bond albedo and with visible-band colors. Comparing the theoretical maximal spin rate of a fluid body with our amplitude versus spin-rate distribution suggests that, if held together only by self-gravity, most asteroids are in general less dense than ~2g/cm^3^, while C types have a lower limit of between 1 and 2g/cm3. These results are in agreement with previous density estimates. For 5-20km diameters, S types rotate faster and have lower amplitudes than C types. If both populations share the same angular momentum, this may indicate the two types' differing ability to deform under rotational stress. Lastly, we compare our absolute magnitudes (and apparent-magnitude residuals) to those of the Minor Planet Center's nominal (G=0.15, rotation-neglecting) model; our phase-function plus Fourier-series fitting reduces asteroid photometric rms scatter by a factor of ~3.
1188. Asteroid masses
- ID:
- ivo://CDS.VizieR/J/AJ/112/2319
- Title:
- Asteroid masses
- Short Name:
- J/AJ/112/2319
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The orbits of 4583 main belt asteroids are integrated orbits for 57 years and searched for asteroid-asteroid encounters from which it may be possible to determine the masses of 23 of the largest asteroids (diameter>=200km) and 11 smaller asteroids. The search is conducted using a scattering formula which serves as a useful filter for identifying encounters that can lead to a mass determination. A total of 460 such encounters were found. The ten most useful of these encounters are examined in detail. The results show that, to make a reliable mass determination, the mean distance of the perturbed asteroid must be known to within a few times 10^-8^AU. An observing program targeting the asteroids listed here would have a substantial impact on our knowledge of asteroid masses and densities.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A59
- Title:
- Asteroid models reconstructed from ATLAS phot.
- Short Name:
- J/A+A/643/A59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Asteroid Terrestrial-impact Last Alert System (ATLAS) is an all-sky survey primarily aimed at detecting potentially hazardous near-Earth asteroids. Apart from the astrometry of asteroids, it also produces their photometric measurements that contain information about asteroid rotation and their shape. To increase the current number of asteroids with a known shape and spin state, we reconstructed asteroid models from ATLAS photometry that was available for approximately 180000 asteroids observed between 2015 and 2018. We made use of the light-curve inversion method implemented in the Asteroids@home project to process ATLAS photometry for roughly 100000 asteroids with more than a hundred individual brightness measurements. By scanning the period and pole parameter space, we selected those best-fit models that were, according to our setup, a unique solution for the inverse problem. We derived ~2750 unique models, 950 of them were already reconstructed from other data and published. The remaining 1800 models are new. About half of them are only partial models, with an unconstrained pole ecliptic longitude. Together with the shape and spin, we also determined for each modeled asteroid its color index from the cyan and orange filter used by the ATLAS survey. We also show the correlations between the color index, albedo, and slope of the phase-angle function. The current analysis is the first inversion of ATLAS asteroid photometry, and it is the first step in exploiting the huge scientific potential that ATLAS photometry has. ATLAS continues to observe, and in the future, this data, together with other independent photometric measurements, can be inverted to produce more refined asteroid models.
- ID:
- ivo://CDS.VizieR/VII/288
- Title:
- Asteroid phase curve coefficients from ATLAS observations
- Short Name:
- VII/288
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Asteroid phase curves are used to derive fundamental physical properties through the determination of the absolute magnitude H. The upcoming visible Legacy Survey of Space and Time (LSST) and mid-infrared Near-Earth Object Surveillance Mission (NEOSM) surveys rely on these absolute magnitudes to derive the colours and albedos of millions of asteroids. Furthermore, the shape of the phase curves reflects their surface compositions, allowing for conclusions on their taxonomy. We derive asteroid phase curves from dual-band photometry acquired by the Asteroid Terrestrial-impact Last Alert System telescopes. Using Bayesian parameter inference, we retrieve the absolute magnitudes and slope parameters of 127012 phase curves of 94777 asteroids in the photometric H, G1, G2- and H, G12*-systems. The taxonomic complexes of asteroids separate in the observed G1, G2-distributions, correlating with their mean visual albedo. This allows for differentiating the X-complex into the P-, M-, and E-complexes using the slope parameters as alternative to albedo measurements. Further, taxonomic misclassifications from spectrophotometric datasets as well as interlopers in dynamical families of asteroids reveal themselves in G1, G2-space. The H, G12*-model applied to the serendipitous observations is unable to resolve target taxonomy. The G1, G2 phase coefficients show wavelength-dependency for the majority of taxonomic complexes. Their values allow for estimating the degree of phase reddening of the spectral slope. The uncertainty of the phase coefficients and the derived absolute magnitude is dominated by the observational coverage of the opposition effect rather than the magnitude dispersion induced by the asteroids' irregular shapes and orientations. Serendipitous asteroid observations allow for reliable phase curve determination for a large number of asteroids. To ensure that the acquired absolute magnitudes are suited for colour computations, it is imperative that future surveys densely cover the opposition effects of the phase curves, minimizing the uncertainty on H. The phase curve slope parameters offer an accessible dimension for taxonomic classification, correlating with the albedo and complimentary to the spectral dimension.
